You have probably heard a lot about the dangers of consuming foods high in sodium, especially in terms of your heart health. When you walk down the aisles in the grocery store, you will see many food options with “low-sodium” or “sodium-free” labels to attract health-conscious buyers. But how often do you see labels promoting an optimal sodium to potassium ratio? As we will see, this is often the more important influence on your health.
Although it is true that a high-sodium diet can be problematic to your health, it does not mean that sodium itself is unhealthy. As with many essential minerals, your body requires it in certain amounts. Sodium’s counterpart is potassium, and the two have a very important partnership that requires a balance. Before we jump into the significance of their yin-yang relationship, let’s review the basics of these two essential minerals.
Unlike many nutrients, the majority of people do not have to worry about sodium deficiencies; the main health concerns come from an excess. The adequate intake level for sodium in teenagers and adults is 1.5 g/day until age 50. The number is lower for children and those over the age of 50.
The Dietary Guidelines for Americans, 2015, recommends individuals consume less than 2,300 mg per day, while the World Health Organization (WHO) recommends less than 2,000 mg per day of sodium, which equals 5 grams of salt. Based on data from the NHANES 2007 – 2010, only 5 percent of the population consumed less than 1,500 mg/day of sodium. The data had not changed significantly in the past 10 years, with the average intake exceeding the recommended maximum of 2,300 mg per day. In a cross-sectional, representative sample of adults living in New York City conducted in 2010, 81 percent of the participants consumed more than the recommended limit, with the mean intake at 3,239 mg per day. The data from the 2011 – 2012 NHANES study found that 90 percent of American adults consumed more than 2,300 mg per day of sodium.
For years, public health guidelines have promoted the reduction of sodium in the diet due to the association between high-sodium diets and hypertension, stroke, and other cardiovascular problems. The number one source of sodium is salt, or sodium chloride. However, this generally does not come from people adding salt as they cook or after a meal is prepared; it comes from added salt during the preparation of processed foods, which have become an increasing component of the average American’s diet. According to one study looking at data from NHANES 2007 – 2010, two categories of food, “grain products” and “meat, poultry, fish, and mixtures,” provided 2/3 of the total sodium intake. The addition of two more categories, “milk and milk products” and “vegetables” increases that number to 4/5 of the sodium sources.
But what does sodium actually do in the body, and why is it necessary? Sodium plays a key role in cellular homeostasis and fluid balance in the body. However, for this to happen, you need less than 500 mg per day. It is also the major extracellular ion and is involved in an important pump that regulates the movement of molecules in and out of the cell for essential body processes, including free calcium concentration, membrane potential, and cell volume.
Although rare, it is possible to have a sodium deficiency. When the levels of sodium in the blood are low, it’s known as hyponatremia. Symptoms include:
– Cognitive issues
– Muscle spasms
– Nausea and vomiting
Symptoms generally occur when there is excessive loss of sodium or excessive fluid compared to sodium. It most commonly occurs when excess water is consumed without sodium and other electrolytes after excessive sweating, such as during intense exercise. It can also occur after severe instances of diarrhea or vomiting.
Potassium is sodium’s counterpart. It is the major intracellular ion and also plays a key role in the sodium pump that regulates key body processes. The pump is also called the sodium-potassium pump or the sodium-potassium-activated adenosine triphosphatase protein complex. This complex uses ATP energy to move three sodium ions out of the cell and two potassium ions into the cell, which then allows for nutrients and metabolites and other ions to have the energy to move across the cellular membrane. This also regulates cellular volume.
Additionally, potassium is involved in:
– Blood pressure regulation
– Bone health
– Heart contractions
– Muscle contractions
The adequate intake of potassium is 4.7g/day for adults. The number is lower for children and young teenagers and higher for lactating women. Yet very few American adults reach this level. Based on the data from the 2011 – 2012 NHANES, the average potassium intake in American adults is 2,800 mg per day. Less than 3 percent achieved the 4,700 mg per day intake recommendation.
Potassium deficiency occurs when blood levels drop below 3.5 mEq/L. The most common causes are chronic diarrhea and excessive use of laxatives or diuretics, although certain illnesses also increase the risk of low potassium levels. Symptoms include:
– Excessive thirst
– Heart palpitations
– Low blood pressure
– Muscle weakness or cramping
– Numbness or tingling
– Vomiting or nausea
The Sodium/Potassium Ratio: Why It Matters
As discussed, a large percentage of the population consumes too much sodium and too little potassium, leading to a high sodium to potassium ratio. This trend begins in childhood, with one study looking at preschool children in the U.S. finding 79 percent of children between 1 and 3 years of age and 87 percent of children 4 to 5 years of age exceeding the upper limit of sodium. The same study found that only 5 percent of children 1 to 3 years of age and 0.4 percent of children 4 to 5 years of age met the adequate intake level of potassium, although 97 percent of infants did. Based on data from the 2011 – 2012 NHANES study, only 1/10 of the American population had a sodium to potassium ratio in line with the WHO guidelines, which is 1:1.
The major reason high quantities of sodium become dangerous to your health is the impact on blood pressure. A healthy sodium to potassium ratio can help mitigate some of this risk. In fact, a recent systematic review found that the sodium to potassium ratio was more strongly associated with blood pressure levels than either mineral on its own, at least in hypertensive adults.
In a study looking at sodium levels and sodium to potassium ratios in prehypertensive patients, both high sodium levels and high sodium to potassium ratios had positive associations with an increased risk of hypertension and cardiovascular disease. Prehypertension was defined as a systolic blood pressure between 120 mmHg and 129 mmHg and/or a diastolic blood pressure between 80 mmHg and 89 mmHg. Prehypertension has been found to be an independent risk factor for coronary heart disease and stroke, and those who are prehypertensive have a two-fold risk of becoming hypertensive compared to those with normal blood pressure.
Using 24-hour urine collection, the researchers measured the sodium and potassium excretion levels. They also took blood samples to test for inflammatory cytokine levels. The participants were followed for 29 months, plus or minus 6 months. The researchers found the following associations:
– Increased sodium led to increased sodium-potassium ratio
– Increased dietary sodium and increased prevalence of diabetes mellitus
– Higher sodium levels and an increase in BMI, triglycerides, and C-reactive protein (an inflammatory marker)
– Increased sodium to potassium ratio and increased triglycerides and more severe coronary artery stenosis
– Increased sodium levels and sodium/potassium ratio and increased IL-6 expression
Another study found significant correlations between sodium and potassium intake and their ratio and blood pressure. For every increase of one standard deviation (SD) (or 25.6 mmol) of sodium intake, there was an associated increase of 1.39 mmHg systolic blood pressure. For potassium, a 1-SD (3.4 mmol) increase of potassium intake correlated with a decrease of 1.42 mmHg systolic blood pressure. Any 1-unit increase in the sodium to potassium ratio led to an increase of 0.97 mmHg in systolic blood pressure. There was a similar trend with diastolic blood pressure: 1-SD increase of sodium led to 0.94 mmHg increase of diastolic blood pressure. For potassium, an increase of 1-SD decreased diastolic blood pressure by 0.91 mm Hg, and for a 1-unit increase in the ratio, there was an increase of 0.65 mmHg of diastolic blood pressure. Only potassium intake and the ratio of the two minerals had a significant association with an increased risk of hypertension.
A similar association is found in adolescents as well. In a nationally representative study of young adolescents aged 12 to 14 years using data from NHANES 1999 to 2012, high levels of sodium consumption and low levels of potassium were both risk factors for high systolic blood pressure. A high sodium to potassium ratio was also associated with a higher risk of high systolic blood pressure. For this study, a high ratio was defined as at or above 2.5. Even when adjusting for multiple variables, the association between the ratio and high blood pressure remained more so than the association with the individual minerals. In this study, only 27.2 percent of the 12 to 14 year olds met the recommended intake of sodium, and only 4.2 percent met the recommendations for potassium.
A high sodium to potassium ratio is also associated with an increased risk of stroke. In one study looking at adult New Yorkers, the hazard ratio in those with a higher sodium to potassium ratio was 1.6 for stroke, including ischemic stroke. Among the over 2,500 participants, the mean sodium to potassium ratio was 1.22.
Additional Health Factors
High sodium intake is also associated with a higher excretion of calcium in the urine, which could impact bone health, among other health factors. Higher potassium intake helps through improving the balance of calcium and phosphorus while also reducing bone reabsorption and increasing bone formation rate. One study in China looked to see if the sodium to potassium ratio also impacted bone mineral density in middle-aged adults. The researchers collected data through food frequency questionnaires and urinary samples to determine the sodium to potassium ratio and performed bone-mineral-density scans. They found that in women, there was a gradual decrease in the BMD, except for in the femur neck, when the sodium to potassium ratio increased, although it was not the same for men. This was more pronounced in those who did not engage in much physical activity.
A high sodium to potassium level also increases the risk of obesity. One study found that there was a direct association between total body fat using DXA screens rather than BMI and urinary sodium to potassium ratio that was independent of other risk factors, including blood sugar, diabetes, blood pressure, and serum triglycerides. They found that this association was greater in non-African Americans, which could mean race might play a factor in the susceptibility to obesity based on dietary choices, at least in terms of sodium and potassium.
Net Dietary Acid Load
For the body to undergo its normal processes, there must be the right pH balance. Different areas of the body have different pH levels. For example, the stomach contains hydrochloric acid to break down food, so it will create a very low pH environment. The blood pH should be close to neutral, with the normal range between 7.35 and 7.45. When the blood drops lower than this, it becomes acidic and might lead to a condition known as acidosis. When it becomes higher, the blood becomes alkaline.
Many studies have connected the modern Western diet with a higher risk of developing mild metabolic acidosis, which interrupts the blood pH balance. It develops when the body enacts compensatory processes to restore the acid/base balance, but the need outweighs the ability of the body to create sufficient bicarbonate acid for buffering. This generally is due to a higher consumption of acidic foods, especially animal protein, without sufficient quantities of alkaline foods to balance it. Researchers have linked this mild metabolic acidosis to a higher risk of diabetes, insulin resistance, metabolic syndrome, chronic kidney disease, end stage renal disease, hypertension, low bone mineral density in older men, and cardiovascular risk independent of the diet.
So, how does this tie into a discussion about sodium and potassium and their relationship with one another? Well, for one, a food’s acidogenic potential is generally calculated using two formulas: PRAL and NEAP. PRAL looks at the nutrient ionic balance, the absorption rates of protein, potassium, phosphorous, magnesium, and calcium, and the sulfate production from metabolized protein. A potentially acid-forming food is positive and an alkaline-forming food is considered negative. NEAP considers the intake of potassium and protein to determine the potential for forming endogenous acid. Foods rich in potassium and magnesium, which are generally plant-based foods, help reduce the net acid dietary acid load, helping to balance the acid potential of animal protein foods and potentially improve metabolic acidosis. Thus, potassium levels greatly impact the risk of metabolic acidosis through providing a buffer to maintain the acid/base balance.
Sodium impacts the acid balance in the opposite way. It reduces the ratio of sodium to chloride, which in turn also reduces the capacity of the body to properly buffer the increased acid load. One study found that IV infusions of sodium chloride induced metabolic acidosis, and another found that oral ingestion of sodium chloride to an alkaline diet led to an increase in the ratio of plasma chloride to bicarbonate, which is a marker for acid/base balance. The additional sodium chloride levels also lead to a reduction in the set point at which the body regulated the bicarbonate levels independent of any change to the NEAP.
An additional study reviewed the ability of sodium chloride to induce metabolic acidosis and found that the urine chloride excretion and renal acid net excretion independently predicted the acid-base balance in a systemic level. These represented the dietary sodium chloride and dietary net acid load respectively. There was an independent association between the increased intake of sodium chloride and acidosis, with the potential for salt to have between 50 and 100 percent of the ability to produce acidosis compared to a net acid-producing diet, if the findings reflect a causal relationship. The researchers postulated that this means there are three predictable factors involved in metabolic acidosis: a dietary net acid load, a high intake of sodium chloride (from food and discretionally addition of salt), and the age-related decline of the regulatory functions for acid/base balance in the body.
Therefore, a high intake of potassium and a low intake of sodium, leading to a more optimal sodium to potassium ratio, also helps to reduce the risk of metabolic acidosis and associated diseases.
What You Can Do
Although there is no standard for an optimal sodium to potassium ratio set by the major organizations such as WHO or the Institute of Medicine, the general recommendation is to increase potassium and decrease sodium intake. If you take the adequate intake levels listed above, then the sodium to potassium ratio would be 1.5 g/day to 4.7 g/day, or 1:3.13 or 0.32. Based on the WHO recommendations of less than 2 g/day of sodium (or 5g/day of salt) and 3.510 g/day of potassium, that ratio would become 1:1.75 or 0.60. The WHO does state that a general guideline for the ratio should be close to 1:1.
So, when you meal plan to create an ideal ratio, you want to aim for two to three times the amount of potassium as you have sodium to keep your ratio within this range, although at the minimum it should be an equal one to one ratio.
As always, it is best to start with a food-first approach. With these particular minerals, you might not need to supplement, as it is very easy to get sufficient quantities from foods, as long as you follow a healthy, plant-based diet with little to no processed foods.
Foods Rich in Sodium and Potassium
Sodium is generally easy to consume in food. For one, you simply have to add some salt to your food. The best type of table salt is a high-quality sea salt, as it has a lower association with hypertension than refined salt.
Foods that are naturally rich in sodium, in order from greatest to least, include:
– Leafy greens, especially Swiss chard
– Sweet potatoes
The range of sodium in a cup or serving of these foods is 73 mg to 120 mg, which is a big difference from processed foods that generally have thousands of milligrams of sodium per serving.
For most people, the goal is to reduce sodium intake rather than increase it. It is common knowledge that processed foods generally have salt in them, even if you do not expect it, such as in certain packaged sweets. Many studies demonstrate that the 70 to 80 percent of sodium consumption comes from processed foods rather than sodium naturally found in food or added salt during cooking or eating. These foods also have a low level of potassium, leading to a very high sodium to potassium ratio. That is why the best thing you can do to help your sodium to potassium ratio is to limit your intake of processed foods—ideally avoid them completely!
One place you might forget about is food from restaurants. It is common for chefs to add copious amounts of salt when they prepare food, especially at restaurants and fast food places that rely on fast preparation and a lot of pre-prepared foods. Therefore, the foods you eat at restaurants most likely have higher levels of sodium.
Potassium is found in abundance in many plant foods, so if you eat a plant-based diet, you can generally get sufficient potassium for your diet. You do not even have to resort to eating bananas to do so. In fact, the following potassium-rich foods, which are listed in greatest to least, all have more potassium per 1 cup or general serving than a banana, the fruit with a reputation for its high potassium content:
– White beans
– Lima beans
– Black beans
– Kidney beans
– Sundried tomatoes
– Dried prunes
– Swiss chard
– Sweet potatoes
Supplementing: What You Need to Know
For sodium and potassium, supplementing is generally not necessary or recommended unless there is a particular health issue. Most people consume sufficient sodium through their diets. However, there might be some benefit to supplementing with potassium for some people. According to a systematic review and meta-analysis, long-term “moderate” supplementation with potassium salts had some benefits to lowering blood pressure in hypertensive patients, especially those who had a baseline potassium intake under 90 mmol/day. Supplementing led to a decrease of 4.48 mmHg systolic BP and 2.96 mm Hg diastolic blood pressure, which was not a dose-response relationship. Those who had a higher sodium intake or a higher sodium to potassium ratio also had a better result with potassium supplementation.
In another study, the results of potassium supplementation were better in those who also lowered sodium intake, leading to a reduced sodium to potassium ratio. In this meta-analysis of random controlled trials, supplementation of between 60 to 100 mmol per day, which led to a total daily intake between 75 and 125 mmol/day, led to decreases in blood pressure in non-medicated patients of 4.7 mmHg SBP and 3.5 mmHg DBP.
Getting a balanced sodium to potassium ratio is relatively easy to do: cut back on (or avoid!) processed foods and increase your intake of vegetables and fruit. With a better sodium to potassium ratio, you decrease your risk of developing many of the common chronic diseases, including hypertension, cardiovascular disease, diabetes, and osteoporosis. As an added bonus, you also help your acid/base balance, which also protects you from disease.
Where should you start? With increasing your potassium intake. One study found that higher intakes of potassium mitigated the increased blood pressure related to increased sodium consumption. In those who consumed more than 6 g/day of salt, the individuals in the fourth quartile (consuming the highest levels) of potassium had a reduction of 6 mmHg systolic blood pressure and 4 mmHg diastolic blood pressure than those in the first quartile of potassium intake. The same study found that those with the highest sodium to potassium ratio had an increase of 8 mmHg and 7 mmHg systolic and diastolic blood pressure levels respectively compared to the lowest quartile.
If you decide to supplement to help your balance, especially with potassium, be sure to discuss it with your doctor first to avoid any potential adverse events or other complications that might arise depending on your own unique situation.
Rainbow Foods & Supplement Course
Do you love learning about how a balance of colorful nutrients can help you thrive? Please join me this January for the Rainbow Foods & Supplements Course, where I’ll guide you in the fascinating scientific research in the food, eating, and supplement fields, and how to create more balance to live more healthfully, creatively, and colorfully!